Aprogramming languageis aformal language, which comprises aset of instructionsthat produce various kinds ofoutput. Programming languages are used incomputer programmingto implementalgorithms.

Most programming languages consist ofinstructionsforcomputers. There are programmable machines that use a set ofspecific instructions, rather thangeneral programming languages. Early ones preceded theinvention of the digital computer, the first probably being the automatic flute player described in the 9th century by thebrothers MusainBaghdad, during theIslamic Golden Age.[1]Since the early 1800s, programs have been used to direct the behavior of machines such asJacquard looms,music boxesandplayer pianos.[2]The programs for these machines (such as a player piano's scrolls) did not produce different behavior in response to different inputs or conditions.

Thousands of different programming languages have been created, and more are being created every year. Many programming languages are written in animperativeform (i.e., as a sequence of operations to perform) while other languages use thedeclarativeform (i.e. the desired result is specified, not how to achieve it).

The description of a programming language is usually split into the two components ofsyntax(form) andsemantics(meaning). Some languages are defined by a specification document (for example, theCprogramming language is specified by anISOStandard) while other languages (such asPerl) have a dominantimplementationthat is treated as areference. Some languages have both, with the basic language defined by a standard and extensions taken from the dominant implementation being common.